/*
silverPDF is sponsored by Aleyant Systems (http://www.aleyant.com)

silverPDF is based on PdfSharp (http://www.pdfsharp.net) and iTextSharp (http://itextsharp.sourceforge.net)

Developers: Ai_boy (aka Oleksii Okhrymenko)

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above information and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR SPONSORS
BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

*/
#region PDFsharp - A .NET library for processing PDF
//
// Authors:
//   Stefan Lange (mailto:Stefan.Lange@pdfsharp.com)
//
// Copyright (c) 2005-2008 empira Software GmbH, Cologne (Germany)
//
// http://www.pdfsharp.com
// http://sourceforge.net/projects/pdfsharp
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
// DEALINGS IN THE SOFTWARE.
#endregion

using System;
using System.Diagnostics;
using PdfSharp.Internal;
using PdfSharp.Pdf.IO;
using PdfSharp.Pdf.Internal;

namespace PdfSharp.Pdf.Filters
{
  /// <summary>
  /// Applies standard filters to streams.
  /// </summary>
  public static class Filtering
  {
    /// <summary>
    /// Gets the filter specified by the case sensitive name.
    /// </summary>
    public static Filter GetFilter(string filterName)
    {
      if (filterName.StartsWith("/"))
        filterName = filterName.Substring(1);

      // Some tools use abbreviations
      switch (filterName)
      {
        case "ASCIIHexDecode":
        case "AHx":
          if (Filtering.asciiHexDecode == null)
            Filtering.asciiHexDecode = new ASCIIHexDecode();
          return Filtering.asciiHexDecode;

        case "ASCII85Decode":
        case "A85":
          if (Filtering.ascii85Decode == null)
            Filtering.ascii85Decode = new ASCII85Decode();
          return Filtering.ascii85Decode;

        case "LZWDecode":
        case "LZW":
          if (Filtering.lzwDecode == null)
            Filtering.lzwDecode = new LzwDecode();
          return Filtering.lzwDecode;

        case "FlateDecode":
        case "Fl":
          if (Filtering.flateDecode == null)
            Filtering.flateDecode = new FlateDecode();
          return Filtering.flateDecode;

        //case "RunLengthDecode":
        //  if (Filtering.RunLengthDecode == null)
        //    Filtering.RunLengthDecode = new RunLengthDecode();
        //  return Filtering.RunLengthDecode;
        //
        //case "CCITTFaxDecode":
        //  if (Filtering.CCITTFaxDecode == null)
        //    Filtering.CCITTFaxDecode = new CCITTFaxDecode();
        //  return Filtering.CCITTFaxDecode;
        //
        //case "JBIG2Decode":
        //  if (Filtering.JBIG2Decode == null)
        //    Filtering.JBIG2Decode = new JBIG2Decode();
        //  return Filtering.JBIG2Decode;
        //
        //case "DCTDecode":
        //  if (Filtering.DCTDecode == null)
        //    Filtering.DCTDecode = new DCTDecode();
        //  return Filtering.DCTDecode;
        //
        //case "JPXDecode":
        //  if (Filtering.JPXDecode == null)
        //    Filtering.JPXDecode = new JPXDecode();
        //  return Filtering.JPXDecode;
        //
        //case "Crypt":
        //  if (Filtering.Crypt == null)
        //    Filtering.Crypt = new Crypt();
        //  return Filtering.Crypt;

        case "RunLengthDecode":
        case "CCITTFaxDecode":
        case "JBIG2Decode":
        case "DCTDecode":
        case "JPXDecode":
        case "Crypt":
          Debug.WriteLine("Filter not implemented: " + filterName.ToString());
          return null;
      }
      throw new NotImplementedException("Unknown filter: " + filterName);
    }

    /// <summary>
    /// Gets the filter singleton.
    /// </summary>
    public static ASCIIHexDecode ASCIIHexDecode
    {
      get
      {
        if (Filtering.asciiHexDecode == null)
          Filtering.asciiHexDecode = new ASCIIHexDecode();
        return Filtering.asciiHexDecode;
      }
    }
    static ASCIIHexDecode asciiHexDecode;

    /// <summary>
    /// Gets the filter singleton.
    /// </summary>
    public static ASCII85Decode ASCII85Decode
    {
      get
      {
        if (Filtering.ascii85Decode == null)
          Filtering.ascii85Decode = new ASCII85Decode();
        return Filtering.ascii85Decode;
      }
    }
    static ASCII85Decode ascii85Decode;

    /// <summary>
    /// Gets the filter singleton.
    /// </summary>
    public static LzwDecode LzwDecode
    {
      get
      {
        if (Filtering.lzwDecode == null)
          Filtering.lzwDecode = new LzwDecode();
        return Filtering.lzwDecode;
      }
    }
    static LzwDecode lzwDecode;

    /// <summary>
    /// Gets the filter singleton.
    /// </summary>
    public static FlateDecode FlateDecode
    {
      get
      {
        if (Filtering.flateDecode == null)
          Filtering.flateDecode = new FlateDecode();
        return Filtering.flateDecode;
      }
    }
    static FlateDecode flateDecode;

    //runLengthDecode
    //ccittFaxDecode
    //jbig2Decode
    //dctDecode
    //jpxDecode
    //crypt

    /// <summary>
    /// Encodes the data with the specified filter.
    /// </summary>
    public static byte[] Encode(byte[] data, string filterName)
    {
      Filter filter = GetFilter(filterName);
      if (filter != null)
        return filter.Encode(data);
      return null;
    }

    /// <summary>
    /// Encodes a raw string with the specified filter.
    /// </summary>
    public static byte[] Encode(string rawString, string filterName)
    {
      Filter filter = GetFilter(filterName);
      if (filter != null)
        return filter.Encode(rawString);
      return null;
    }

    /// <summary>
    /// Decodes the data with the specified filter.
    /// </summary>
    public static byte[] Decode(byte[] data, string filterName, FilterParms parms)
    {
      Filter filter = GetFilter(filterName);
      if (filter != null)
        return filter.Decode(data, parms);
      return null;
    }

    /// <summary>
    /// Decodes the data with the specified filter.
    /// </summary>
    public static byte[] Decode(byte[] data, string filterName)
    {
      Filter filter = GetFilter(filterName);
      if (filter != null)
        return filter.Decode(data, null);
      return null;
    }

    /// <summary>
    /// Decodes the data with the specified filter.
    /// </summary>
    public static byte[] Decode(byte[] data, PdfItem filterItem)
    {
      byte[] result = null;
      if (filterItem is PdfName)
      {
        Filter filter = GetFilter(filterItem.ToString());
        if (filter != null)
          result = filter.Decode(data);
      }
      else if (filterItem is PdfArray)
      {
        PdfArray array = (PdfArray)filterItem;
        foreach (PdfItem item in array)
          data = Filtering.Decode(data, item);
        result = data;
      }
      return result;
    }

    /// <summary>
    /// Decodes to a raw string with the specified filter.
    /// </summary>
    public static string DecodeToString(byte[] data, string filterName, FilterParms parms)
    {
      Filter filter = GetFilter(filterName);
      if (filter != null)
        return filter.DecodeToString(data, parms);
      return null;
    }

    /// <summary>
    /// Decodes to a raw string with the specified filter.
    /// </summary>
    public static string DecodeToString(byte[] data, string filterName)
    {
      Filter filter = GetFilter(filterName);
      if (filter != null)
        return filter.DecodeToString(data, null);
      return null;
    }
  }
}
